Plug injector apparatus



May 20, 1969 c. A. PITTS 3,444,928

PLUG INJECTOR APPARATUS Filed Nov. 3, 1967 INVENTOR. Char/e5 6'. P/f/sUnited States Patent US. Cl. 166-70 3 Claims ABSTRACT OF THE DISCLOSUREThis invention relates to cement plug injector apparatus which isadapted to be rotated if desired. The plugs are enclosed in sleeves inthe device which drop into place and seat in alignment with the wellcasing as the retainer elements are moved to the plug injectionposition.

This invention relates to plug injector apparatus and particularly toapparatus used for injecting so-called cementing type plugs into thecasing of earth wells during a well treating operation.

In conventional cementing plug injector apparatus the plug or plugs areusually held in position in the injector apparatus by means of a pinwhich extends across the apparatus either through or below the plug.Extraction of the pins is often difficult to accomplish in a timelymanner because the pressures encountered during the cementing or othertreating operation cause the pin to bind as it is being retracted.

Accordingly, a principal object of this invention is to provide animproved plug injector apparatus for use in treating earth wells.

Another object of this invention is to provide an improved, easy toactuate plug injector apparatus for use in treating earth Wells.

In accordance with this invention there is provided plug injectorapparatus comprising a hollow cylindrical body section adapted toreceive a plug of the so-called cementing plug type. Cement enters thebody section from the top thereof.

The plug or plugs are disposed within a sleeve which is of smallerdiameter than the inner diameter of the body section. The plug isaxially aligned with the longitudinal axis of the body section and isheld in position prior to its release by an arcuate (generallycircularly shaped) element which extends across the diameter of the bodysection with its convex part facing upwardly and supporting the lowerpart of the plug.

Means are provided for rotating the arcuate element from a positionWhere the elements convex part faces upwardly generally along thelongitudinal axis of the body section to where the arcuate element liesperpendicular to the longitudinal axis of the body section along thewall of the body section. The sleeve then seats against the arcuateelement and the plug is then forced, by pressure exerted from above,down the body section, past the arcuate element and into the well casing(not shown).

The invention, as well as additional objects and advantages thereof,Will best be understood when the following detailed description is readin connection with the accompanying drawing, in which:

FIG. 1 is a side elevational view, in section, of injector apparatusmade in accordance with this invention, and

FIG. 2 is a sectional View taken along the line 22 of FIG. 1.

Referring to the drawing, there is shown plug injector apparatus,generally indicated by the numeral 10. The apparatus comprises anelongated generally tubular body section, indicated generally by thenumeral 12, which has side walls 14 and threaded upper and lower ends16, 18, respectively.

The upper end 16 is adapted to receive fluid or pumpable cement slurryfrom a pipe or rotatable swivel head assembly (not shown). The lower end18 is adapted to be coupled to a casing string, for example, which is tobe cemented in place in a well bore (not shown).

The upper end 10 of the body 16 may have a bushing 18 which adapts thebody section to be coupled to a swivel head, as mentioned above, whichis usually coupled to drill pipe rather than casing.

Arcuate, generally circularly shaped plug retaining and seal elements20, 22 are disposed in the body section 12 intermediate the endsthereof.

The height of the circular part of the elements 20, 22 is a minor partof their inner diameter. The elements 20, 22 have diametricallyoppositely disposed pins 24, 26 and 28, 30, respectively. The pins 24,28 are each journalled in bores 32, 34, respectively, in the side wallsof the body section. The pins 26, 30 are each mechanically coupled torotatable shafts 36, 38, respectively which extend through bores 40, 42,respectively, in the side walls.

The means for rotating the shafts 36, 38 may be the lever arms 44, 46,respectively, or remotely controlled means (not shown) coupled to theouter ends of the shafts 36 or 38, for example.

The shafts 36, 38 each have an O-ring type seal 48, 50 respectively andare held in place by suitable retainer and rotation limiting elements52, 54, respectively.

Each of the plug retaining and seal elements 20, 22 are disposed withthe periphery of the circular parts of the elements disposed on an upand down position across the inner diameter of the body section ratherthan aligned parallel with the side walls of the body section 12 whenthe elements 20, 22 are in the retaining position.

A cementing plug 56, 58 is disposed in a slidable but close fittingmanner within a sleeve element 60, 62, respectively, which is of smallerdiameter than the inner diameter of the body section 12. Each of theplug-sleeve assemblies are retained on an element 20 or 22 within thebody section 12 until they are to be forced from the apparatus and downthe well casing, for example.

The diameter and wall thickness of the sleeves 60, 62 are the same (atleast usually). The sleeves fit loosely in the body section to permitcement to flow around the sleeves and into the well casing until suchtime as each plug is to be introduced into the casing.

In operation, with a cement line (not shown) coupled to the upper end ofthe body section and the lower end of the body section coupled to wellcasing (not shown), fluid or cement is pumped through the apparatusbetween the sleeves '60, 6'2 and the inner wall of the body section.

When it is desired to introduce the first plug 58 into the casing, theretainer-seal element 22 is rotated until the edges of the circular partof the element 22 are aligned with the seat 64 of a reduced innerdiameter part of the lower end of the body section. The inner diameterof the lower end part 66 of the body section is at least approximatelythe same as the diameter of the well casing and equal to the innerdiameter of the sleeve 62.

When the element 22 is turned, the sleeve 62 seats against the upperpart of the circular part of the element 22. Then, because the seatingof the circular part of element 22 on seat 64 and the seating of thesleeve 62 against element '22 shuts off substantially all fluid flowthrough the apparatus, pressure on the fluid (or cement slurry) forcesthe plug 58 down through the sleeve and into the well casing.

When suflicient material has been introduced after the plug 58 is in thecasing, the retainer element 20 may be rotated to be disposed inalignment with the upper end Further, apparatus may be provided whichhas a single I plug-retainer assembly and which has more than twoplug-retainer assemblies.

The end-feeding feature of this invention permits the use of a swivelhead in conjunction with the apparatus and thus permits the casing to berotated or oscillated as the cementing operation is underway. Suchmovement of the casing is advantageous in many cementing operations.

Because the elements 20, 22 always remain within the body part, theapparatus is safer to use than devices wherein pins are pulled torelease the cementing plugs.

What is claimed is:

1. Plug injector apparatus for use in earth well cementing or treatingoperations, comprising an elongated, generally tubular body sectionhaving an upper end, a lower end, and side walls extending between saidends, upper and lower annular shaped elements rotatably disposed in saidbody section with the axis of rotation of said elements beingperpendicular to the longitudinal axis of said body section, meansexternal of said body section for rotating said annular shaped elements,said annular shaped elements being of equal inner and outer diametersand of substantially smaller outer diameter than the inner diameter ofsaid body section above said lower annular element, said inner diameterof said body section lying between said lower end and the lower annularshaped element being of substantially the same diameter as the innerdiameter of said annular shaped element and having a tapered seat-likeend part adjacent to said lower annular shaped element, a pair of openended sleeve elements, said sleeve elements having the same outer andinner diameters as said annular shaped elements and each having a lengthdimension permitting said sleeve element to fit in said body section,one sleeve element being disposed between said annular shaped membersand the other sleeve element being disposed between said upper end andsaid upper annular shaped member, said sleeve element each beingsupported on a side of one of said annular shaped elements, a pair ofplug elements, one of said plug elements being disposed in each of saidsleeve elements in frictional engagement with the side walls thereof,means for coupling said lower end to well casing, and means forintroducing pumpable material into said upper end.

2. Apparatus in accordance with claim 1, wherein the inner diameter ofsaid sleeve element is the same as the inner diameter of the casing ofthe well with which said apparatus is used.

3. Apparatus in accordance with claim 1, wherein said means for rotatingsaid annular shaped elements each comprises a lever actuated shaftextending through the side wall of said body member and mechanicallycoupled to an annular shaped element.

References Cited UNITED STATES PATENTS 2,620,037 12/1952 McClendon166-70 2,630,179 3/1953 Brown 166-70 X 2,713,909 7/1955 Baker 166703,216,500 11/1965 Diehl 166-70 CHARLES E. OCONNELL, Primary Examiner.

J. A. CALVERT, Assistant Examiner.

U.S. Cl. X.R. l5104.06

